Copyrighted Jul. 31, 2002. Provisional patent applied May 17, 2004. Excerpts from the book When Left is Right: Keyboarding to Success by this patent writer and author, Charlene H. Grafton Regardless of type of numerical input device, alternating activity between the right hand and left hand will reduce the load on the right hand during tasks using the usual computer and numerical keypad or the computer with a stand alone numerical input device and/or mouse/pointing device.
Research categories reviewed in this section of the book are anatomy and physiology, brain organization, hand and finger movements, musicians, tactile objects (touch) discrimination, motor dominance, circling tasks, gender, performance, individual differences, old learning and new learning, training and education, left to right directionality, similar studies, musculoskeletal disorders and injury prevention.
One of the more important researchers and an engineer, Eric Haseltine wrote for Discover and Neuroquest in March of 2002 that circling movements between the extremities in clockwise and counterclockwise rotation need explanation: when the neurons controlling your arm and leg on the same side of the body work together, they do not disturb each other, but when you circle on the other side of the body in same direction, you will find it tough to do. Haseltine continues that neuroscientists have not figured out why this happens except to say that dominant regions of the brain take up more neuronal resources than non dominant areas and are therefore are more inconsiderate neural neighbors.
Finally, a summary of expectations and recommendations for learning how to use the numeric keypad and/or mouse with your non preferred hand from the device selection process.
Three/fifths of all occupational injuries can be attributed to various debilitating hand and wrist disorders according to The John Marshall Journal of Computer and Information Law. Without reliable medical or scientific evidence showing a relationship between use and injury, the question arises, is it necessary for computer manufacturers to begin placing warnings on their keyboards which urge users to pay more attention to safety and comfort??
The said OSHA in their eTool website, alternative left hand keyboards which have the keypad permanently affixed to the left side of the keyboard are available as are keyboards with a detached keypad. These allow the user to switch positions for either left or right hand use. Also programmable stand alone keypads are available which can be programmed to facilitate either right or left hand usage as possible solutions. But this arrangement can be limiting to the left handed workers or right handed workers who are recovering from injury and are attempting to remain functional during recovery.
Ainsworth at www.qwerty.com has a patent describing his development of two-handed input systems and his approach to eliminate carpal tunnel and other RSI problems. But this does not mention any interference in the neural network of the fingers in his Ainsworth Keypad Trainer software program. Ainsworth states you can use either hand for the same device just by positioning the keyboard with keypad. But this does not account for our USA culture for reading sequentially left to right and then transposing that old learning to new learning of the non preferred hand. Due to human factors and brain organization this sequential learning for the non preferred hand will either be parallel sequencing or mirror image sequencing based upon the person's dominance.
Springer and Deutsch in their book Left Brain/Right Brain, (two psychologists) state each hemisphere appears to be approximately a mirror image of the other, very much in keeping with the general left right symmetry of the human body. Their theory of control of the body's basic movements and sensations are evenly divided between the two cerebral hemispheres. But they agree that by examining the abilities of our two hands are not equivalent in all respects. Most people have a dominant hand but few people are truly ambidexterous. In humans, preferences will vary.
Researchers agree there are undoubtedly differences in cerebral lateralization and other features of brain organization which correlate with hand preference and proficiency as a trait variable according to Wilkes and Sheely. They propose left handers are a heterogenous group, some having a dominant right hemisphere and others having a dominant left hemisphere. These varying patterns of brain hardware, in interaction with environmental experience in a dominantly right handed culture, are likely to produce differences in the fine structure of movement organization.
When a subject performs a well learned motor act with the less preferred hand, it is unclear whether the reduced proficiency is due to control by a non dominant hemisphere which is somehow less capable or to interference by inappropriate motor commands from the dominant hemisphere from the same Wilkes and Sheely study of finger movements and handedness.
In the Two Mind Theory in how the brain is organized, visualize the right hemisphere is under left hand control with music, fantasy, art, creativity, genius, perception, emotional expression and a holistic thinking mode. Then for the left hemisphere under right hand control is language, writing, logic, mathematics, science with a linear thinking mode.
The said brain organization studies of Hier, LeMay, Rosenberger and Perlo, McRae, Branch and Milner (1978) conclude that handedness and sidedness are apparent in brain scans and show differences.
The Wilke et al study and method will be shown in the method for dexterity training.
The Grafton et al (2002) explained the human right hemisphere is active during execution of contralateral hand movements, and the left hemisphere is engaged for both contra and ipsilateral movements, at least for right handed subjects. Learning with the left hand also recruited a widespread set of temporal and frontal regions suggesting that motor skill learning with the non dominant hand develops within both cognitive and motor related functional networks. In this study using PET scans and the right hands of participants the stimulus sequence and series of response locations remained unchanged, but the finger movements were different.
The Torque Test used by T. Blau and also Franz et al, similar circling tasks used. Franz et al (2003) in their study asking does handedness determine which hand leads in a bimanual task. Their study tested on a bimanual circle task that required drawing either in the same direction (parallel) or in a mirror symmetrical coordination mode with the two hands. The pattern of results was similar for left and right handers on parallel tasks, but group differences were found with respect to mirror symmetrical tasks. At odds with the general claim that the dominant hand leads, the present results indicated that hand dominance does not generally determine which hand leads.
The Cattaert et al (1999) in their cross talk model for between the hand interference during bimanual circle drawing found under the asymmetrical mode (both limbs moving clockwise or counterclockwise) increases in movement frequency have a disruptive effect on trajectory control and hand coordination. Their theory proved the motor systems controlling each hand are prone to neural cross talk.
The Nalcaci et al (2001) in their study of the relationship between handedness and fine motor performance was to re-investigate the relationship between handedness and asymmetry in hand performance and if there is sex difference in motor asymmetry. In the total sample, the correlation between hand speed and the handedness score indicated that the distribution of hand preference is associated with left hand speed, but not right hand speed. Results also confirmed that right handed females tend to have more asymmetric motor function than right handed males.
Levy and Gur in their neurological studies looked at individual differences in psychoneurolgical organization and found that, as expected, writing requires access to the language hemisphere. Thus, the dominant writing hand always appears to be under the control of the language hemisphere. They concluded it would not matter if the control pathways from the language hemisphere lead directly or indirectly to the ipsilateral (same) hand in others, to the contralateral (opposite) hand.
The noted researcher, Stanley Coren, asks Does Society Make Right Handers? Due to the fact of review of their studies, with less and less numbers of left handers that through the years, culture pressure makes right handers out of left handers. From our culture it is a learned response. Dr. Coren writes when we are talking about handedness and hand control, as many as twenty three brain centers and neural pathways are involved. These include several different movement control systems and position sensing systems that originate in the cerebral cortex.
The Nadler et al (2000) in their study of acquisition of a new motor skill from finger muscles (index and little finger) investigated possible reorganization of central nervous pathways of the non dominant hand. Their findings suggested that learning a new motor skill produces changes which take place predominantly in the cortical pathways of the cutaneomuscular reflex and may be due to changed connectivity within the motor and/or sensory cortex.
The Nachshon (1985) is his study of directional preferences may be a function of either reading and writing habits, or hemispheric asymmetry, or both. In this study between English readers and Arabic readers, English readers showed left to right preferences.
The Singh et al (2000) in their reading/writing vs. handedness with children, both left and right handed with differing reading/writing experiences used a drawing task. Results showed lines drawn from left to right were more accurate.
The Ackland and Hendrie (2002), used a computer mouse alternating between the preferred and non preferred hands believing this would be a viable injury prevention strategy within the workplace. They concluded that, three×30 min sessions of training for a period of three weeks was sufficient to improve control of the mouse by the non preferred hand, cause the non preferred hand to reach a level of proficiency equivalent to that of the preferred hand for work related skills and allow a majority of operators to consider alternating mouse activity between the preferred and non preferred hands in a work environment. They further excluded left handers or workers that used two hands for the cursor.
These occupational hazards are found world wide in all kinds of manual jobs. There are no interventions at this time to prevent the primary prevention of carpal tunnel syndrome in a working population. Despite the societal impact of CTS and growing numbers of commercial remedies of alternative keyboard and keypad designs, none have been based on a person's functional dominance.
Ong et al (1995) in their study of occupational disorders and examined the possible causes and suggest preventive strategies as a multidisciplinary approach. This study mentions causes as poor ergonomic design of the workplace and equipment design.
Yu et al (1996) in their study of VDU workers in a Hong Kong bank believe that arm, hand and wrist problems were more affected by repetitive movements and recommend modification of the work station design.
Muggleton et al, (1999) found musculoskeletal disorders are the most common self reported, work related illness in the UK.
The Dr. Sharan, an Indian Orthopedic doctor presented his latest research in the field of Computer Related Injuries (CRI) at the 47th Annual Conference in 2002. He defines CRI as a constellation of work related symptoms in computer users. It is a diffuse disorder of muscle, fascia, tendon and/or neurovascular structures, which typically involve the neck and upper limb. Dr. Sharon conducts on site CRI Clinics and ergonomic consulting for Hewlett Packard at Bangalore whereby he treated over 250 IT professionals. He has successfully treated over 700 CRI and over 700 IT professionals from Compaq, Infosys, IBM, and ISRO have attended his training programs on CRI prevention?.
The Pascarelli et al (1993) in their study of soft tissue injuries related to use of the computer keyboard believed that harmful inefficient keyboard styles (intrinsic ergonomic factors) and changes in the workstation (extrensic ergonomic factors) must be addressed and corrected by a combination of factors including technique retraining and education.
In a presentation by this inventor in 2005 of the American Society of Women Accountants, a survey was used following: results of 85% were right handed, 42% had symptoms of computer related hand complaints, 80% used a computer at home and at work, an average of 15 years of computer use work experience, the Blau handwriting test results of parallel 50% and mirror image 50% and the Wilke-Sheeley finger circling test parallel 25% and mirror image 75%.
In a presentation to fellow professional writers in 2005, the results of this group were 92% used their right hand for writing, 66% had symptoms of hand or finger complaints from writing/computing, 70% used a computer at home, 25% used a computer both at home and at the office, an average of 12.9 years of computer use, the Blau handwriting test results were parallel 75% and mirror image 25% and the finger circling test with parallel 45% and mirror image 55%.
In a presentation to a group of comptrollers, auditors and accountants by this inventor, in 2005, the results showed 69% were right handed, 21% left handed and 8% mixed handed, 47% had hand and finger complaints and 1 shoulder, after testing 39% were mirror/mirror image, 26% were parallel/parallel image, 34% had different mirror/parallel image or parallel/mirror image results.
Following these three presentations of computer users, the invention of the dual systems and the training programs were written for left hand usage. With development of this system of input selection for dual keypadding or dual mice, a great service would be accomplished providing a dramatic downturn in expenses of medical occupational diseases.